______, they couldn’t solve the mystery.
| A．Tried hard as they | B．Hard as they tried | C．Tried as they hard | D．They tried hard as |
I'm certain David's told you his business troubles. ______, it's no secret that he owes a lot of money to the bank.
| A．However | B．Anyway | C．Therefore | D．Though |
Although my grandfather is in his eighties, he is still as ________ as a young man and hates sitting around doing nothing all day.
| A．enthusiastic | B．intelligent | C．energetic | D．sensitive |
—John is very ______ .—if he promises to do something he’ll do it.
| A．independent | B．confident | C．reliable | D．flexible |
In those days, our ________ concern was to provide people who were stopped by the snow storm with food and health care.
| A．normal | B．constant | C．permanent | D．primary |
In my view, London's not as expensive in price as Tokyo but Tokyo is______in traffic.
| A．the most organized | B．more organized |
C．so organized as | D．as organized as |